Oulipo theme, adding link to image

I recently changed themes to Oulipo. This post by thesacredpath was very helpful for inserting an image in the left margin, and so I was wondering what I have to add to the css to have that image he talks about work as a hyperlink? I'd like to use the image as a clickable option to get to my home page rather than creating a 'home' page in the custom menu section itself. Here's the css I currently have added to my site...